BS 4439 Screwed Studs — Metric Series
BS 4439 specifies general-purpose screwed studs in the metric series, with a plain portion between the metal end and nut end.
Selected metric stud thread dimensions
| Thread d | Coarse pitch P (mm) | Metal-end thread for steel lm (mm) | Metal-end thread for weak or brittle housing lm (mm) |
|---|---|---|---|
| M6 | 1.0 | 6 | 9 |
| M8 | 1.25 | 8 | 12 |
| M10 | 1.5 | 10 | 15 |
| M12 | 1.75 | 12 | 18 |
| M16 | 2.0 | 16 | 24 |
| M20 | 2.5 | 20 | 30 |
Reference note: Selected common sizes. The metal-end thread length is d for steel housings and 1.5d for weak or brittle tapped materials. The nut-end thread length depends on the stud diameter and nominal length; consult the full BS 4439 schedule. General-purpose size coverage is M3 to M39.